main(){
  num age01=18;
  print(age01);

  num age=18;
  double age1=18.67;
  print(age+2);
  print(age1+2.5);


  var username='12345';
print('当前用户名:$username');

var isMarry=false;
isMarry? print('已婚'):print('未知');

bool isSingle=true;
print(isSingle);


}